1. Field of the Invention
The present invention relates to an ankle joint and coupling arrangement for artificial limbs designed to enable an amputee to use the artificial limbs with greater facility, and more particularly to enable the amputee to walk more naturally with better balance and more security. The ankle joint of the present invention has a broad circumferential surface around a transverse axis about which movement is obtained which resembles the action of the human ankle. The ankle joint of this invention includes an inverted cup-shaped or curvilinear contoured member attached to the bottom of the leg member for sliding over another inverted cup-shaped member or lateral rocker member engaging the top of the foot which has a longitudinally oriented groove having an arcuate bottom surface. The parts are interconnected by a bolt extending therethrough with the bolt including a lateral motion joint at the upper surface of the foot member.
Also, the invention relates to a combination of an ankle joint and coupling for leg and foot members and in which there is a variable ankle stop for variably adjusting the limits of movement between the leg member and the foot member to accommodate any size shoe, shoe heel, tennis shoes, and the like. The variable ankle stop consists of a bolt member fastened to the leg member and having its extension portion limiting the articulated movement of the leg member with the foot, so that by using simple tools, the user may vary the stop position.
2. Description of the Prior Art
Various prior U.S. patents relate to coupling and joint elements for artificial limbs, and of interest to the present invention are the following U.S. patents:
U.S. Pat. Nos.: 433,497--Aug. 5, 1890--Swank PA1 710,966--Oct. 14, 1902--Peer PA1 975,439--Nov. 15, 1910--Lawrence PA1 1,091,115--Mar. 24, 1914--Blon PA1 1,368,348--Feb. 15, 1921--Moore PA1 2,439,195--Apr. 6, 1948--Witmyer et al PA1 4,089,072--May 15, 1978--Glabiszewski.
The patent to Witmyer et al discloses a series of cup elements for artificial limb joint members which function in a manner providing articulated movement between the members. The other enclosed patents disclose various joints and components used with artificial limbs and none of these patents provide disclosure of all of the specifics of the present invention in such a way as to bear upon the patentability of any claim of the present invention.